Noise attenuation device for a centrifugal compressor discharge or suction nozzle

ABSTRACT

A centrifugal compressor discharge or suction nozzle is provided. The centrifugal compressor discharge or suction nozzle includes a side resonator integrally formed in the centrifugal compressor discharge or suction nozzle. Further, a centrifugal compressor discharge or suction nozzle formed as a pipe section piece adapted to be mounted on a centrifugal compressor, includes a side resonator integrated into the pipe section piece. Furthermore, a centrifugal compressor includes the centrifugal compressor discharge or suction nozzle and/or the pipe section piece. Additionally, a centrifugal compressor arrangement includes the centrifugal compressor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2008/065934, filed Nov. 20, 2007 and claims the benefit thereof. The International Application claims the benefits of European Patent application No. 07022502.4 EP filed Nov. 20, 2007. All of the applications are incorporated by reference herein in their entirety.

FIELD OF INVENTION

The invention relates to a centrifugal compressor discharge or suction nozzle, a centrifugal compressor discharge or suction nozzle formed as a pipe section piece adapted to be mounted on a centrifugal compressor nozzle, a centrifugal compressor comprising the centrifugal compressor discharge or suction nozzle, and a centrifugal compressor arrangement respectively comprising at least one side resonator integrally formed in the centrifugal compressor discharge or suction nozzle, wherein the side resonator(s) act(s) like an acoustic mirror.

BACKGROUND OF INVENTION

In chemical and petrochemical plants a centrifugal compressor is commonly used for pressurising process gas. The centrifugal compressor comprises at least one suction nozzle and at least one discharge nozzle, wherein said nozzles are connected to plant piping. Through the suction nozzle process gas flows into the centrifugal compressor to be compressed therein. The compressed process gas exits the centrifugal compressor through the discharge nozzle to be delivered to downstream plant components.

The centrifugal compressor comprises at least one rotor with at least one impeller. Downstream of the impeller the centrifugal compressor comprises a diffuser. The impeller and the diffuser are aerodynamically effective to compress the process gas. During operation of the compressor the rotor rotates thereby generating noise. The noise is a combination of discrete frequency noise (tonal noise) related to the so-called blade passing frequency and its higher harmonics.

The noise generates a high noise exposure of the environment and can cause structural failures of the centrifugal compressor and the piping due to vibration cracking.

It is desirable to reduce the noise intensity level of the emitted noise spectrum at the blade passing frequency and its higher harmonics. Attenuation of the noise level upstream and downstream of the suction and discharge piping, respectively, will reduce the exposure to the environment and can reduce cyclic stresses in the structures upstream and downstream of the nozzles.

A remedy to reduce the noise intensity level of the centrifugal compressor is to cover the centrifugal compressor with a noise hood. The noise hood is able to reduce the noise exposure of the environment. However, the noise-hood is cost-intensive and needs to be taken into consideration with respect to space requirement being problematic in a plant with limited space.

Another remedy to reduce the noise intensity level of the centrifugal compressor is to provide the downstream piping of the centrifugal compressor with a piping silencer. However, the piping silencer is flown through by the process gas and therefore induces a high flow resistance resulting in an adverse pressure loss. Further, the piping silencer is costly in construction and large in geometrical dimensions. Such a silencer is shown in DE 1814146A1.

Furthermore, another remedy to reduce the noise intensity level of the centrifugal compressor is to provide a Helmholtz array in the diffuser. The Helmholtz array is installed on the diffuser wall resulting in a complicated and cost-intensive centrifugal compressor construction. Such a construction is shown in U.S. Pat. No. 6,575,696 B1.

SUMMARY OF INVENTION

It is an object of the invention to provide a centrifugal compressor discharge or suction nozzle, a centrifugal compressor comprising the centrifugal compressor discharge or suction nozzle, and a centrifugal compressor arrangement comprising the centrifugal compressor, wherein the centrifugal compressor is effectively noise attenuated during operation and cost-effective in construction.

According to the invention, the centrifugal compressor discharge or suction nozzle comprises at least one side resonator integrally formed in the centrifugal compressor discharge or suction nozzle.

Alternatively, according to the invention, the centrifugal compressor discharge or suction nozzle is formed as a pipe section piece adapted to be mounted on a centrifugal compressor nozzle, comprising at least one side resonator integrated into the pipe section piece.

Further, according to the invention, between compressor nozzles and piping various stacked rings can be installed forming one or more side resonator(s).

Furthermore, according to the invention, the centrifugal compressor comprises the centrifugal compressor discharge or suction nozzle.

Additionally, according to the invention, the centrifugal compressor arrangement comprises the centrifugal compressor.

The process gas discharging the centrifugal compressor is interfered by tonal noise generated within the centrifugal compressor during its operation at a specific frequency band. The tonal noise is related to the so-called blade passing frequency and its higher harmonics. The discharge or suction nozzle of the centrifugal compressor comprises the side resonator(s), whereby the side resonator(s) is (are) in direct cooperation with the discharge or inlet process gas. Since the side resonator(s) is (are) appropriate to reduce the tonal noise by the effects of acoustic impedance, the side resonator(s) act(s) like an acoustic mirror at the specific frequency band of the tonal noise. The geometrical dimensions of the side resonator(s) determine the frequency band in which the resonator(s) is (are) active. Therefore, it is possible to attenuate the frequency band in which the blade passing frequency is active. As a consequence of this, during operation of the centrifugal compressor, its noise emission level is lower.

Further, when the process gas flows through the discharge or suction nozzle, the process gas passes the side resonator without disturbing the process gas flow in the discharge or suction nozzle. Therefore, the side resonator includes very low or even less flow resistance to the process gas discharge or suction flow. Hence, a side resonator does not cause any significant pressure loss in the process gas discharge or suction flow. The process gas discharge or suction flow is noise attenuated by the side resonator(s). Consequently, the centrifugal compressor comprising the side resonator has a high energy efficiency.

As an alternative, the side resonator(s) is (are) integrated in the pipe section piece, such that advantageously the centrifugal compressor can be equipped with the side resonator(s) subsequent to its assembly. Further, different types of side resonators can be provided for the centrifugal compressor in replacing the pipe section piece provided with different side resonators, and the pipe section piece can be designed as an universal section which can be mounted on any centrifugal compressor.

As an alternative various rings can be stacked in between the nozzle piping connection forming one or more resonators that can be fitted to any compressor.

Since the side resonator is in the pipe section piece, the centrifugal compressor has a compact design, which is easy and cost saving to be manufactured.

Preferably, the compressor discharge or suction nozzle comprises a plurality of side resonators located after each other. This enlarges the frequency band in which the noise is attenuated and makes the solution most robust.

Each side resonator is capable to reduce a specific frequency. Therefore, by providing a plurality of side resonators after each other, wherein each side resonator can be adapted to reduce another specific frequency, the frequency band in which the plurality of side resonators is effective to reduce the tonal noise, is broadened. This is the reason why the inventive centrifugal compressor is silenced in an effective way by means of the plurality of side resonators.

It is preferred that the pipe section piece comprises a plurality of ring elements having different inner diameters and concentrically adjoining each other, and at least one flange element facing the plurality of ring elements, wherein the plurality of ring elements form the side resonator(s).

The ring elements preferably can be formed by universal rings. Further, preferably standard flange elements can be used, such that manufacturing costs of the pipe section piece are low.

It is preferred that the centrifugal compressor arrangement comprises the centrifugal compressor, wherein the side resonator comprises a liquid injection device for liquid injection into the side resonator for cleaning thereof.

Preferably, the centrifugal compressor arrangement comprises a gas scrubber provided upstream of the centrifugal compressor and a bypass line from the side resonator to the gas scrubber for bypassing the process gas or the liquid from the side resonator to the gas scrubber.

Further, it is preferred that the bypass line comprises a bypass valve.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention is explained on the basis of preferred embodiments with reference to the drawings. In the drawings:

FIG. 1 is a longitudinal section of a third embodiment of a centrifugal compressor nozzle according to the invention,

FIG. 2 is a longitudinal section of a ninth embodiment of a centrifugal compressor nozzle according to the invention,

FIG. 3 is a longitudinal section of a tenth embodiment of a centrifugal compressor nozzle according to the invention,

FIG. 4 is a schematic view of a centrifugal compressor arrangement according to the invention, and

DETAILED DESCRIPTION OF INVENTION

Further, the side resonator according to FIG. 4 comprises a circular resonator 4. The circular resonator 4 is a disc-shaped cavity encompassing the centrifugal compressor nozzle 1.

For the side resonator any shape is possible provided its effective length is such that the desired noise attenuation is possible. Therefore, the side resonator do not need to be rotation symmetric but can comprise an eccentrically formed cylindrical resonator 6.

FIGS. 1 to 3 show a pipe section piece 10. The pipe section piece 10 is adapted to be mounted on a centrifugal compressor nozzle. Therefore, when the pipe section piece is mounted on the centrifugal compressor nozzle, process gas entering or discharging the centrifugal compressor passes through the pipe section piece 10. FIG. 2 shows one of many possible variants of the pipe section piece 10.

The pipe piece section 10 according to FIG. 18 is integrally formed and comprises a pipe 11 and two flanges 12 provided on the longitudinal ends of the pipe 11. The flanges 12 are adapted to be fitted to the centrifugal compressor nozzle. The pipe 11 has an inner diameter 15.

Further, in the pipe 11 three circumferentially extending ring grooves are provided thereby forming three circular resonators 4 to 4″ integrated into the pipe section piece 10, respectively. Each circular resonator 4 to 4″ has an inner diameter 13 to 13″, respectively, being greater than the inner diameter 15 of the pipe 11, wherein the inner diameter 13 is smaller than the inner diameter 13′, and the inner diameter 13′ is smaller than the inner diameter 13″. The circular resonators 4 to 4″ are arranged side by side such that the pipe piece section is acoustically effective for a broad frequency band.

The number and shape of the resonators 4 to 4″ can be varied depending on the desired acoustic characteristic of the pipe section piece 10. In FIGS. 2 and 3 i designates the number of resonators, Ø designates the diameter of the resonator i, t_(i) designates the width of the resonator i, and L, designates the distance between the resonator i and the resonator i+1.

The pipe piece section 10 according to FIG. 3 is similar to the pipe piece section 10 according to FIG. 2, but comprises seven individual ring elements 14, 14′, 14″, 14′″, 14 ^(IV), 14 ^(V), 14 ^(VI). The inner diameter of the ring elements 14, 14″ 14 ^(IV), 14 ^(VI) equals the inner diameter 15 of the pipe 11. The ring elements 14′, 14′″, 14 ^(V) have different inner diameters 13 to 13″ and are concentrically adjoined together. Further, the pipe piece section 10 according to FIG. 3 comprises two flange elements 12 facing the ring elements 14, 14′, 14″, 14′″, 14 ^(IV), 14 ^(V), 14 ^(VI) for being adapted to be mountable to a centrifugal compressor nozzle.

The seven ring elements 14, 14′, 14″, 14′″, 14 ^(IV), 14 ^(V), 14 ^(VI) are stacked and form the circular resonators 4, 4′, 4″. Any other number of ring elements 14, 14′, 14″, 14′″, 14 ^(IV), 14 ^(V), 14 ^(VI) is possible.

As a further option, the centrifugal compressor nozzle 1 comprises a wash water injection device 28 for wash water injection into the side resonators 4 and 4′ for cleaning thereof. Further, the centrifugal compressor arrangement 20 comprises a gas scrubber 24 provided upstream of the centrifugal compressor 21 and a bypass line 29 from the centrifugal compressor nozzle 1 to the gas scrubber 24. By means of the bypass line 29 a gas flow can be forced through the pipe section piece 10 to the gas scrubber 24. Further, the bypass line 29 comprises a bypass valve 30 for controlling the bypassed gas flow. Additionally, wash water is fed back to the scrubber 24 via the bypass line 29. 

1.-11. (canceled)
 12. A centrifugal compressor discharge or suction nozzle, comprising: a side resonator integrally formed in the centrifugal compressor discharge or suction nozzle, wherein the side resonator acts like an acoustic mirror, wherein the centrifugal compressor discharge or suction nozzle is fowled as a pipe section piece adapted to be mounted on a centrifugal compressor, the centrifugal compressor comprising the side resonator integrated into the pipe section piece, wherein the pipe section piece comprises one or a plurality of ring elements including a plurality of different inner diameters and concentrically adjoining each other, and a flange element facing the plurality of ring elements, and wherein the plurality of ring elements form the side resonator.
 13. The centrifugal compressor discharge or suction nozzle as claimed in claim 12, wherein the side resonator is integrally formed in the pipe section piece.
 14. The centrifugal compressor discharge or suction nozzle as claimed in claim 12, wherein the compressor discharge or suction nozzle comprises a plurality of side resonators located one after another.
 15. The centrifugal compressor discharge or suction nozzle as claimed in claim 14, wherein each side resonator comprises an array of single tube resonators circumferentially distributed.
 16. The centrifugal compressor discharge or suction nozzle as claimed in claim 14, wherein the side resonator comprises a circular resonator.
 17. The centrifugal compressor discharge or suction nozzle as claimed in claim 15, wherein each side resonator comprises a circular resonator.
 18. The centrifugal compressor as claimed in claim 12, wherein the side resonator comprises an eccentrically formed cylindrical resonator.
 19. The centrifugal compressor discharge or suction nozzle as claimed in claim 12, wherein the side resonator is a resonator adapted to include self cleaning properties.
 20. A centrifugal compressor, comprising: a centrifugal compressor discharge or suction nozzle, comprising: a side resonator integrally formed in the centrifugal compressor discharge or suction nozzle, wherein the side resonator acts like an acoustic minor, wherein the centrifugal compressor discharge or suction nozzle is formed as a pipe section piece adapted to be mounted on the centrifugal compressor, wherein the side resonator is integrated into the pipe section piece, wherein the pipe section piece comprises one or a plurality of ring elements including a plurality of different inner diameters and concentrically adjoining each other, and a flange element facing the plurality of ring elements, and wherein the plurality of ring elements form the side resonator.
 21. The centrifugal compressor as claimed in claim 20, wherein the side resonator is integrally formed in the pipe section piece.
 22. The centrifugal compressor as claimed in claim 20, wherein the compressor discharge or suction nozzle comprises a plurality of side resonators located one after another.
 23. The centrifugal compressor as claimed in claim 22, wherein each side resonator comprises an array of single tube resonators circumferentially distributed.
 24. The centrifugal compressor as claimed in claim 22, wherein the side resonator comprises a circular resonator.
 25. The centrifugal compressor as claimed in claim 23, wherein each side resonator comprises a circular resonator.
 26. The centrifugal compressor as claimed in claim 12, wherein the side resonator comprises an eccentrically formed cylindrical resonator.
 27. The centrifugal compressor as claimed in claim 20, wherein the side resonator is a resonator adapted to include self cleaning properties.
 28. A centrifugal compressor arrangement, comprising: a centrifugal compressor, comprising: a centrifugal compressor discharge or suction nozzle, comprising: a side resonator integrally formed in the centrifugal compressor discharge or suction nozzle, wherein the side resonator acts like an acoustic mirror, wherein the centrifugal compressor discharge or suction nozzle is formed as a pipe section piece adapted to be mounted on the centrifugal compressor, wherein the centrifugal compressor comprises a side resonator integrated into the pipe section piece, wherein the pipe section piece comprises one or a plurality of ring elements including a plurality of different inner diameters and concentrically adjoining each other, and a flange element facing the plurality of ring elements, and wherein the plurality of ring elements form the side resonator, and wherein the side resonator comprises liquid injection device for liquid injection into the side resonator for cleaning thereof.
 29. The centrifugal compressor arrangement as claimed in claim 28, further comprising a gas scrubber provided upstream of the centrifugal compressor and a bypass line from the side resonator to the gas scrubber for bypassing a liquid from the side resonator to the gas scrubber.
 30. The centrifugal compressor arrangement as claimed in claim 29, wherein the bypass line comprises a bypass valve.
 31. The centrifugal compressor arrangement as claimed 29, further comprising an additional gas scrubber provided upstream of the centrifugal compressor. 